Is Personality Skin Deep?

Research shows that couples may look like they share personality traits.

We are drawn to people whom we match in attractiveness, and we tend to pair up with partners of a similar age. It’s therefore unsurprising that independent observers rate couple members as similar in attractiveness and age. But research shows that partners also look like they possess similar personalities.

Recently, a team of psychologists from Hong Kong revealed the importance of personality to judgments of physical similarity.

Yetta Kwailing Wong and her colleagues took portrait photographs of 60 male-female couples who had been married between six months and 35 years. Next, they obscured the hair and clothing in each photograph, leaving just the face visible. Then they gathered together another group of men and women to rate the photographs. These independent judges saw photographs in pairs. Half of the time, the pairs of photographs represented real couples; the other half of the time, male and female faces were paired randomly. The judges were asked to rate the similarity of each pair of faces, based on attractiveness, age, and apparent personality.

The results of the study showed that the real couples did look similar in perceived personality. However, most of this similarity effect could be explained by age. This is because certain personality traits are thought to be more pronounced at different ages. For example, extroverted young people or emotionally stable older people. Wong’s judges may have thought some partners were similar in personality mostly — but not entirely — because they were similar in age.

Interestingly, real couples were no more likely to match on attractiveness than fake couples. This means that partners are more similar in apparent personality than in physical attractiveness.

In a follow-up experiment, Wong made a new set of face pairs. This time she paired each of her original couple-members with someone whose personality was more similar than their partner’s and with someone whose personality was less similar than their partner’s (she took care to choose people who were similar in age and attractiveness to the real partner).

A new group of judges looked at these two types of fake couples, as well as the real couples, and rated them for similarity.

Wong found that fake couples with closely matched personalities were judged more similar in appearance than fake couples with poorly matched personalities. This confirms that apparent personality does have an effect on how similar a couple looks. Still, the real couples were judged to be more similar than both types of fake couple. Clearly something other than personality, age, and attractiveness causes couples to look alike.

Earlier research by psychologists from the UK also shows that judgments of personality based only on appearance are fairly accurate, although more so for some personality traits than others. People who look like extroverts usually are. Judgments of emotional stability and openness to experience are also usually accurate, although only for male faces.

A new phenomenon I think, probably to do with the extent to which we have become self obsessed. I have noticed that gay men almost always choose similar partners. They even dress and groom alike. Gay women not so much. They still go for opposites. Genetically we are wired to be attracted to people who are different, because the offspring are healthier, so it's not good for people to choose similar mates for breeding. But obviously getting what you want is all that matters these days.

I can't comment on your observation on patterns on mate choice among same gender couples, but "genetically, we are wired" might be overstating it. No evolutionary psychologist, despite being open to the influence of genes on behaviour, would be so genetically determinist: in short, any genetic predispositions will interact with environment to produce behaviour. Also, you make a fair point about attraction to others, but the consensus view is that there are also advantages to choosing a similar partner (cooperation may be greater among similar people): many people talk about "optimal outbreeding", which describes the tension between choosing a mate who is too different or too similar.